Seeking video player or editor that can reproduce video at slow motion without sacrif

voice tones I believe is the best way to describe. first of all please help me with the terminology I am missing here with the quality of the sound I'm trying to retain. would it be the pitch... actually i believe its the frequency that determines the the quality of voices that would keep the normal (tone?) so,

1) would this be correct? and also,

2) what would be the terminology for the technology of an editing program or player that retains the normal frequency/pitch of a voice while slowing it down?

any help with this subject would greatly be appreciated. ideally if I could find a player compatible with windows mobile 6.1 that could do this conveniently on the fly would be great. i'm learning spanish to be able to take a spanish video and slow it down without having the voices sound like you are on drugs is what i'm aiming for. i actually accomplished this with premiere a couple years ago so now that i think of it i guess i did accomplish partially answering my question. but a player that does this with the press of a button would be so much easier. thanks in advance